Olfaction Flashcards
(67 cards)
What are the two ways that sense of olfaction can be stimulated?
-Orthonasal-inspiration via the nose (Odour)
-Retronasal-via the mouth during consumption(Aroma)
What are the four steps in the olfactory system?
- Odorants bind to receptors.
- Olfactory receptor cells are activated and send electric signals
3.The signals are relayed in glomeruli - The signals are transmitted to higher regions of the brain
During respiration or when air refluxes retronasally, where are voltalies directed?
Into the nasal cavity below the level of the olfactory epithelium.
What is olfactory epithelium a part of?
The mucosa
What is the shape of an olfactory receptor cell?
Long, narrow, and column shaped.
What is the diameter of an olfactory cell?
Less than one micron.
What type of cell is an olfactory cell?
A neuron
what is the lifespan of an olfactory cell?
About one month
How many receptors cells are on either side of the nose?
About 3 million.
what are the steps of the transduction process of the olfactory system?
The signal firstly comes to olfactory bulb, then reaches to piriform cortex(primary cortex), then to orbitofrontal cortex. The secondary process goes to the thalamus.
If stimulus—->action potential—>nerve tract—->sensory cortex, then how do we get different qualities =(submodalities) within a sense?
This is the computational problem of univariance.
what is the step of this univariance?
Odorants–>action potential—>olfactory nerve—->olfactory cortex
How many odour compounds in Strawberry?
11
How many odour compounds in Strawberry?
1000
What is a remarkable ability of the olfactory system?
It can recognize and discriminate a vast array of odors, even at extremely low concentrations.
What system is the olfactory system comparable to in terms of discrimination ability?
A: The immune system.
The immune system.
How is the olfactory system similar to the immune system?
Both can discriminate an immense variety of molecules—odors in the olfactory system and epitopes on antigen molecules in the immune system.
What is specificity coding?
Representation of a specific stimulus by the firing of specifically tuned neurons specialized to just respond to a specific stimulus.
What is population coding?
Representation of a particular object by the pattern of firing of a large number of neurons.
What is population/combinatorial encoding in the olfactory system?
A small number of olfactory receptors (ORs) can interact with and respond to numerous odorants in diverse combinatorial manners.
How do different smells get represented in the olfactory system?
Different patterns of activated glomeruli correspond to distinct smells.
What is an odor threshold?
The lowest concentration of a chemical in the air that people can detect.
What factors influence odor acuity?
The physical and chemical properties of compounds.
Is odour acuity generalized across all odorants?
No, it varies based on the specificity of each compound.